This invention relates to an apparatus and a method for chromatographic separation. More in particular, it relates to an improved process and apparatus for the separation of polar species by liquid adsorption chromatography with a re-usable column packing.
Chemical separation of species of differing polarity by column adsorption chromatography has become a widely used technique, for example, in the area of pesticide residue analysis. The common procedure has been to pass a solution containing the species to be separated through a column containing a porous adsorbent material such as silica gel to preferentially adsorb one of the species. In order to re-use the adsorption column for additional separations, the adsorbed species are manually removed from the column, and the column or at least its packing discarded. A typical method is shown in an article by W. B. Crummett and R. H. Stehl in Environmental Health Perspectives, September 1973, pp. 15-25.
The manual techniques are inefficient and impractically slow, and are thus unacceptable for commercial applications. Furthermore, such techniques are more likely to cause exposure to the typical pesticides separated by these methods which can be highly toxic to humans. It is therefore desired to develop a new and automated process for repetitive use of a single charge of particulate porous adsorbent material in a liquid adsorption column for the separation of species of differing polarity commingled in solution.